Note: Descriptions are shown in the official language in which they were submitted.
CA 02482286 2004-09-23
TAMPER-RESISTANT CONTAINER AND METHODS
This . application is a continuation-in-part of co-pending and co-owned U.S.
Application No. 10/669,677 of the same title filed September 23, 2003,
incorporated herein by
reference in its entirety.
Copyright
A portion of the disclosure of this patent document contains material which is
subject to copyright protection. The copyright owner has no objection to the
facsimile
reproduction by anyone of the patent document or the patent disclosure, as it
appears in the
Patent and Trademark Office patent files or records, but otherwise reserves
all copyright
rights whatsoever.
Background of the Invention
1. Field of the Invention
This invention relates generally to the field of containers adapted to
selectively
restrict access thereto, and specifically in one exemplary aspect to animal-
proof containers
for supplies and other materials including, inter alia, food.
2. Description of Related Technology
Under many circumstances, it is desirable to store supplies and materials in a
container
such that access to the supplies or materials is selectively controlled. This
is true of a broad
variety of materials including _ chemicals, pharmaceuticals, and notably
supplies taken on
outdoor excursions. One particularly difficult application of such "selective
access"
technology relates to the storage of food and supplies during hiking and
camping excursions
into wilderness areas where animals are present. Many of these animals,
including most
notably members of the ursa species (commonly referred to as bears), are
amazingly adept at
gaining access to such storage containers: Instances of bears ripping apart
containers and even
automobiles to get at food stored within are now commonplace. The bear is
particularly adept
at leveraging its great strength, weight, sharp teeth and claws to gain access
to literally any
type of container. Bears are often excellent climbers as well, thereby
affording them
substantial mobility in all three dimensions.
While not only destructive and costly, such surreptitious access by bears is
also
detrimental to the bear population, since {i) the bears can become dependent
on the ill-gotten
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CA 02482286 2004-09-23
food provided by humans, thereby reducing their ability and tendency to obtain
food via
natural sources; and (ii) the bears can become increasingly aggressive in
their attempts to
obtain food, thereby sometimes necessitating their termination as a danger to
humans. Aside
from the foregoing, even a "low intensity" encounter with . a bear seeking
food can be
traumatic to the hiker or camper, and represents another danger thereto. Many
a camping or
hiking trip has also been ruined through unexpected loss of supplies, even
where no
confrontation occurs.
Accordingly, more extreme measures have been implemented in recent years to
mitigate the foregoing detriments and threats to both humans and bears. For
example, Federal
law now requires proper storage of food throughout National Parks (such as the
well known
Yosemite National Park). The National Park Service strongly advises all
backpackers to
carry and use approved bear-resistant food storage canisters instead of other
traditional
methods such as slinging the food/supplies over an elevated tree limb, etc. In
some areas
use of bear-proof canisters is required (such as above certain elevations
within Yosemite):
In response to the aforementioned surreptitious intrusion and access to food
and
supplies by bears, a variety of different"bear exclusion" technologies have
arisen over the
years. These are generally classified into three (3) discrete categories: (i)
anti-bear
canisters; (ii) anti-bear bags; and (iii) hanging or elevated storage. , These
devices are
generally subject to approval by relevant oversight organizations such as
SIBBG or SEKI.
Several different types of anti-bear canisters have been developed or
proposed.
Three commercially available types include the Garcia Model 812 Backpackers'
Cache, the
so-called "Bearikade" manufactured by Wild Ideas, Inc., and the Tahoe model
from Purple
Mountain Engineering, Ino, of Palmdale, CA.
The Model 812 device 100 (Fig. 1) is generally cylindrical in shape, yet with
a
decided taper from the center region 102 toward its ends (thereby giving
somewhat of a
"beer barrel" appearance). The completely opaque (black) device is
manufactured via an
injection molding process, wherein two half sections are formed of a polymer
(Acrylonitrile Butadiene Styrene, or ABS) and then bonded together via an
adhesive. In
terms of access, one end of the container includes an aperture 104
significantly smaller than
the outer diameter of the container, thereby creating a fairly broad rim or
lip 106 around the
periphery of the aperture. An access hatch or cover 108 is mated into the
aperture, using an
insert tab and two opposed, mechanically actuated locking mechanisms I 10 to
secure the
cover in place. A screwdriver, coin, or other similar device is required to
actuate the
mechanisms.
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Unfortunately, the Model 812 device suffers from several disabilities,
including the
aforementioned taper of the container, which makes carrying very difficult
(e.g., restraining
straps tend to slide off the container due to the taper). A corresponding
carrying case is sold
(Model C-12 Carrying -Case) in order to carry the Model 812 device, attesting
to its
difficulty to carry or restrain without an external case. Whether by design or
otherwise, this
approach adds additional cost to the solution.
The Model 812 design also utilizes the aforementioned cover as part of the
structural integrity of the container, the cover 108 bearing some of any
compressive force
applied to the container as a whole. Unfortunately, the cover can be dislodged
when enough
lateral compressive force is applied (such as a heavy bear standing on the
side of the device
with its weight on its front paws). This effect results primarily from
differential distortion
of the container and the cover.
Another disability associated with the Model 812 device is due to the
aforementioned cover 108 being recessed in an aperture is the tendency for
rainwater to
collect in this recess and enter the container, wetting and spoiling the
contents.
Another disability associated with the Model. 812 device is the substantially
restricted access provided to the user. Specifically, the thick rim or Iip 106
previously
described acts to make items inserted ox removed via the aperture more likely
to catch or be
hung up on the rim. This is especially true of non-cylindrical or round items,
such as
freeze-dried food pouches or the like. The edges of such items tend to catch
on the rim of
the container, thereby requiring the user to fold or bend the item for easier
insertion/removal. This is particularly frustrating and debilitating when
removing the.items
from the container, since the aperture is sized not much larger than the
diameter of the
average human fist, thereby making manipulating such items awkward (or
otherwise
necessitating "pre-forming".them, such as by using rubber bands or the like).
Additionally, the locking mechanisms 110 of the Model 812 are difficult to
operate,
and require a separate tool. They also must be properly aligned to replace the
cover onto
the container body, and are potentially subject to fouling with dirt or other
foreign
materials. Such locking mechanisms are also comparatively expensive to
manufacture.
Additionally, the need to bond the two half sections of the Model 812 together
also
requires a substantial butt joint that introduces extra bulls and weight to
the design with a
reduction in useful interior volume (and therefore food capacity).
Lastly, the Model 812 device is also comparatively heavy, owing in large part
to the
injection-molded/adhesive technology it utilizes. Specifically, in order for
the-container
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CA 02482286 2004-09-23
(and particularly the bonded seam) to sustain sufficient Lateral or
longitudinal loading, the
container material must be made comparatively thicker, especially since it is
designed for
minimum flexing (i.e., the ABS is not very flexurally robust). This added
thickness
significantly increases the weight of the container. .
The aforementioned "Bearikade~" device 200 (Fig. 2) has a generally similar
construction to the IVIodeI 812, in that it is substantially cylindrical, and
utilizes rotated
locking mechanisms 202 to seal the cover 204 to the canister 206. See the
discussion of
United States Patent No. 6,343,709 provided subsequently herein. However, its
shape is
cylindrical (no seeming taper), and the cont~.iner is fabricated using a
comparatively
complex and expensive technology. Specifically, the container is made of a
composite
sandwich using an offset seam, taper rolling technique. The container is also
cured in
autoclave at elevated temperature and pressure. The Bea,rikade end components
principally
consist of a 6061 T-6 aluminum hatch, locking collar, and end fittings bonded
to the
composite carbon-fiber cylinder with high strength epoxy. O-rings are used
between the
fasteners and hatch, and between the hatch and locking collar. When sealed
properly (the
seal must not have any debris on the O-rings), the O-rings are under
compression and offer
a seal against water.
While having good access at the access aperture, the Bearikade device suffers
primarily from high cost and complexity of manufacturing, the former being
several times
the cost of the Model 812 device previously described. It (Bearikade)
similarly uses
mechanically actuated locking mechanisms (3) which must be operated with a
tool or coin.
Furthermore, the device is not well adapted to climatic changes in pressure;
the
aforementioned O-rings, while useful for preventing water intrusion (due in
part to the
pressure differential across the Gover acting to more tightly seal the O-rings
when the
canister is submerged), also , can make the device difficult to open when it
is sealed at
higher elevation (lower pressure), and then transported. to a lower elevation
~ (higher
pressure). This "vacuum bottle" effect is highly undesirable.
The Purple Mountain Engineering (PME) "Tahoe" bear canister is made from 6061
aluminum. The canister body is heat treated after assembly, and, the top is
TIG (Tungsten
Inert Gas) welded to the canister body. The cover (lid) is hinged (stainless
steel riveted to
the top and Lid}. Closure of the lid is accomplished by a DZUS fastener rated
at 600 pounds
closure force. As with the other prior art solutions, the Tahoe suffers from
several
disabilities, including complexity, comparatively high cost and heavy weight
(two pounds,
six ounces) and small capacity.
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The so-called "Ursack~" device is generally representative of the state-of the-
art
in anti-bear sack technology. The Ursaclc TKO model is made of spectra fabric
and
bolstered with flexible fiberglass ripstop. The standard Ursack is made from
aramid fibers
woven to enhance puncture and tear resistance to ostensibly thwart a bear's
teeth, claws,
and strength. However, the Ursack has the flaws of providing no rigid support
to protect
l
the materials contained within, and the aramid or other fibers are
comparatively costly to
manufacture. The Ursack has also proven less than completely effective at
frustrating bear
intrusion, and also requires that the device be tied to a tree or other
immovable structure
(lest the bear merely carries the sack off for latex efforts at intrusion).
Sae the discussion of
Unified States Patent No. 6,332,713 provided subsequently herein.
A variety of technologies related to animal exclusion and tamper-
resistant/sealed
containers are present in the patent prior art as well. For example, United
States Patent No.
4,203,479 to Mathews issued May 20, 1980 and entitled "Trash bag protector"
discloses a
device for protecting filled trash bags from attacks by dogs or other animals.
The device
has a collapsible mesh frame composed of interv~oven plastic strands and which
presents an
open top defined by an upper rim. The open top is closed by eight equally
spaced straps
whose outer ends are attached to the rim. The inner end of one of the closure
straps is
provided with an upstanding post upon which the inner ends of the other straps
can be
installed. Thus installed, the straps extend radially outwardly from the post
to the rim and
may be locked in place, thereby securing the bags in the protector device.
United States Patent No. 4,801,039 to McCall, et al. issued January 31, 1989
and
entitled "Animal proof container" discloses an animal proof container
comprising a can
having a bottom, a sidewall having an inside surface having a plurality of
substantially flat
portions each having a recess defined thereby, an outside surface having a
corresponding
plurality of holes communicating to the recesses and a rim defining an open
top. A lid of
the container has a cover portion adapted to cover the open top of the can and
a plurality of
members extending downwardly peripherally from the cover portion, fitting adj
acent the
inside surface of the can and having lower end portions adjacent the flat
portions of the
inside surface, the lower end portions being biased outwardly towards the flat
portions
sufficiently to proceed into the recesses when the lid is pushed fully
downwardly onto the
can. The lid is biased normally upwardly relative to the can sufficiently for
preventing the
lower end portions from entering the recesses. Food stored in such a container
is ostensibly
protected from the attacks of animals, includirig_large animals such as bears.
The container
can also be made relatively light in weight.
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United States Patent No. 5,344,109 to Hokoana, Jr. issued September d, 1994
and
entitled "Apparatus for the engagement and suspension of a bag above the
ground for the
suspendable storage of items within the bag" discloses an apparatus for
suspending
conventional trash bags and other bags above the ground. for the storage
and/or disposal of
a variety of items including camping supplies and food. The apparatus
comprises a support
frame for securing the rim of the bag thereta and suspension arms coupled to
the support
frame through the use of engagement hooks for hanging the bag above the
ground. The
support frame comprises a first aperture for insertion of t:he rim of the bag
therethrough, the
rim wrapped around the sides of the support frame such that the bag opens
through the first
aperture. To protect the items inside the bag from weather and animals, the
apparatus
further includes a cover frame with a second aperture disposed on top of the
support frame
and a lid for covering the second aperture. With this arrangement, the
engagement hooks
are used to engage and secure the corresponding corners of the support frame
and the cover
frame with the rim of the bag firmly secured therebetween. The apparatus may
further
include upholding means for coupling one end of the suspension aims together
and
engaging a support structure for suspension of the apparatus, the upholding
means
comprising one of a variety of attachment members and having a length
adjustment
member for facilitating attachment of the apparatus to an appropriate support
structure.
United States Patent No. 5,411,161 to Fish, Jx. issued May 2, 1995 and
entitled
"Container having a twist-locking cover" discloses a refuse device includes a
cover which
can be lacked to the container of the device by rotating the cover on the
container. The
cover includes a top portion, a collar extending downwardly from the top
portion, and two
tabs attached. to the collar, spaced apart from the top portion, located
opposite each other,
and extending inwardly from the collar. The container includes a sidewall
terminating in an
upper edge, a closed bottom attached to the sidewall opposite the upper edge,
an outwardly
extending rim attached to the upper edge of the sidewall, and an upwardly
extending lip
attached to the rim opposite the sidewall. The lip includes two diametrically
opposite
channels through which the tabs move when the cover is placed on or removed
from the
container. The lip also includes six grooves, two of which flank the first
channel, two of
which flank the second channel, and two of which are positioned intermediate
the first and
second channels. The latches rest within the' two intermediate groove when the
cover is first
placed on the container. The latches rest in two of the grooves flanking the
channels when
the cover is locked to the container. In this locked position, the cover
cannot be lifted from
the container, and resists rotation on the container.
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United States Patent No. 5,638,977 to Bianchi issued June 17, 1997 and
entitled
"Assembly for securing a lid to a container" discloses a lid to be attached to
a container, a
garbage can for example, wherein the lid is secured by means of a system
comprising holes
placed in the lid rim in alignment with corresponding holes in the top of the
container. A
conduit is provided on the underside of the lid in alignment with the holes in
the lid and the
holes in the container. A securing rod passes through the conduit and the
holes in the lid
and container to secure the lid to the container. In use, the holes of the lid
rim and the holes
of the container are in registration with each other.
United States Patent No. 5,950,981 to Judy issued September 14, 1999 and
entitled
"Bear bag system" discloses a bear bag system for protecting a supply of food
while
camping. The device includes a length of nylon rope having opposing free ends.
A bag of
rocks is securable to one, of the free ends of the length of nylon rope. Two
supplemental
bags are provided for storing food. Two lengths of curtain cord adjustably
couple the
supplemental bags with respect to the length of nylon cord. ,
United States Patent No. 6,332,713 to Cohen issued December 25, 2001 and
entitled
"Lightweight bear bag" discloses a lightweight food sack (e.g., the
aforementioned
"Ursack") made from puncture and tear resistant fabric sewn with high strength
thread and
secured with an abrasion resistant cord. The food sack is closed by tightening
the cord,
which encircles the top of the sack in a hem and emerges through a grommet.
The cord is
secured by means of a cord lock and an overhand knot (20). Excess cord is then
tied with a
secure lrnot to a fixed object, such as a tree, so that the sack cannot be
removed by a bear.
United States Patent No. 6,343,709 to DeForrest, et al. issued February 5;
2002 and
entitled "Impact resistant sealable container" discloses an impact resistant,
sealable canister
(the aforementioned "Bearikade" being one embodiment thereof) comprising a
wall
structure having a lower edge portion joined to a base. A receiving collar is
joined to an
opposing top edge portion of the wall structure. The receiving collar includes
an annular
channel and an inner shoulder having fastener pads. The pads have fastener
openings and
stationary connector elements. A container lid releasably seals against the
collar by
operation of fastener parts retained in the lid that engage the collar
connector elements.
Gasket materials adjacent the collar periphery and around the fastener parts
function to
provide a reusable sealed canister useful for water activities and other
outdoor
involvements. -
Despite the variety of different techniques existing under the prior art,
there still
exists a need for an animal exclusion container, ideally having the following
attributes: (i)
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CA 02482286 2004-09-23
light weight; (ii} low cost; (iii) ease of access (i.e., no particular tools
required); (iv) ready
access for objects of varying shape and composition); (iv} ease of carrying;
and (v) climatic
flexibility and resistance.
S Summary of the Invention
The present invention satisfies the aforementioned needs by providing an
improved
tamper-resistant lightweight apparatus and methods far operating, handling and
manufacturing the same.
In a first aspect of the invention, an improved animal excluding apparatus is
disclosed, generally comprising: a body having an interior volume and an
aperture formed
therein; and a threaded cap having at least one locking element associated
therewith; wherein
the cap threads onto the body. In one exemplary embodiment, the body and cap
are each one-
piece molded polymer components, with the body being a rugged yet lightweight
and low cost
polycarbonate, and the cap being formed of glass-reinforced nylon. 'The cap is
designed to be
very low profile; and virtually eliminate any gap between itself and the body
that the animal
might exploit. An exclusion ridge is formed proximate to cap at the gap;
thereby further
frustrating attempts by the animal to pry the cap off the body. The cap and
body are each
sufficiently rugged and flexible to withstand the onslaught of a full grown
bear without
compromise or damage to the components (or the bear).
In a second aspect of the invention, an improved animal-resistant cap is
disclosed. In
one exemplary embodiment, the cap comprises a unitary, low profile, threaded
component
formed of a lightweight polymer (e.g., glass-reinforced nylon) and having a
locking element
adapted to cooperate with a corresponding element formed on the body of the
container on
which the cap is threaded. In a second embodiment, the cap comprises an
assembly having an .
outer (cap) element and an inner ring structure; the cap element and ring
structure cooperate to
allow opening of the container (removal of the cap) under the application of
downward force
coupled with rotation.
In a third aspect of the invention, a method of operating an animal excluding
container
is disclosed. In the exemplary embodiment, the container has a body and
threadedly engaged
cap, the container comprising first and second interfering locking elements,
and the method
generally comprises: applying force to the cap in at least one region to
reduce the interference
between locking elements; and rotating the cap in cooperation with the act of
applying, the
rotating causing the locking elements to change relative position thereby
allowing further
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CA 02482286 2004-09-23
- rotation of the cap. The locking elements comprise, e.g., raised features
disposed on the cap
and body proximate one another. By distorting the cap slightly and rotating
the cap at the
same time, sufficient clearance between the raised features is created,
thereby allowing them
to pass one another (and unlock the cap). This movement requires dexterity not
present in a
bear or most other species.
In another embodiment, the locking elements comprise a cooperating cap and
ring
structure which require coordinated application of downward force along with
rotation of the
cap.
In a fourth aspect of the invention, an improved method of manufacturing a
tamper-
resistant container apparatus is disclosed. In the exemplary embodiment, the
method
comprises: forming a unitary body having ari aperture therein and a first
locking element
thereon; forming a cap element adapted to threadedly engage the body, the cap
element
having a second locking element thereon, and threading the cap element onto
the body such
that the first and second locking elements cooperate to frustrate subsequent
removal of the
cap by other than adult humans. In the exemplary embodiment, the body is
formed (as one
piece) from polycarbonate using a first molding process, while the cap is
formed from
glass-reinforced nylon using a second molding process. This highly simple
process,
coupled with choice of low-cost materials and simple but effective design,
significantly
reduces the cost of manufacturing the container as compared to prior art
solutions.
In a fifth aspect of the invention, an improved container with enhanced
protection
against inadvertent cap removal is provided. In one exemplary embodiment, the
container
utilizes a retaining mechanism (e.g., tab) formed on the container body
proximate the cap,
which frustrates outward (radial) deflection of the cap sidewalk thereby
avoiding such
inadvertent or unwanted cap removal (pop-offj.
In a sixth aspect of the invention, an improved container with enhanced
protection
against inadvertent cap removal is provided. In one exemplary embodiment, the
container
utilizes a support mechanism (e.g., ring) formed on the container cap which
rides just inside
the mouth or thread area of the body when the cap is threaded thereon. This
ring supports
the thread area against deflection of the body thread area wall, thereby
avoiding cap pop-off
under even heavy load conditions.
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CA 02482286 2004-09-23
These and other features of the invention will become apparent from the
following
description of the invention, taken in conjunction with the accompanying
drawings.
Brief Description of the Dravvi~
Fig. 1 is a perspective view of a first exemplary prior art animal exclusion
container
(Garcia Model 812):
Fig. 2 is a perspective view of a second exemplary prior art animal exclusion
container ("Bearikade").
Fig. 3 is an exploded perspective view of a first exemplary embodiment of the
tamper-resistant container apparatus according to the present invention.
Fig. 3a is a cross-sectional view of the apparatus of Fig. 3 (when assembled),
taken
along line 3-3.
Fig. 3b is a partial {detail) cross-sectional view o.f the apparatus of Fig.
3, also taken
along line 3-3, showing the cap and thread area.
1 S Fig. 3c is a top perspective view (partial) of the apparatus of Fig. 3,
showing an
exemplary loclcing element configuration.
Fig. 3d is a front plan view of the apparatus of Fig. 3
Fig. 3e is a partial perspective view of another embodiment of the container
apparatus, illustrating an exemplary "loop" retention element configuration.
Fig. 4 is perspective view of a second exemplary embodiment of the tamper-
resistant container apparatus according to the present invention, including
two-piece cap
assembly.
Fig. 4a is a crass-sectional view of the apparatus of Fig. 4 (when assembled),
taken
along line 4-4.
Fig. 4b is a partial {detail) cross-sectional view of the apparatus of Fig. 4,
also taken
along line 4-4, showing the cap assembly and thread area.
Fig. 4c is a front plan view of the apparatus of Fig. 4.
Fig. 4d is a side plan view of an exemplary embodiment of the cap assembly
ring
structure of the embodiment of Fig. 4
Fig. 4e is a top plan view of the ring structure of Fig. 4d.
Fig. 4f is a partial side cross-sectional view of the ring structure of Fig.
4d, showing
interior threads.
Fig. 4g is a side cross-sectional view of the exemplary cap element of the
embodiment of Fig. 4, taken along line 4-4.
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CA 02482286 2004-09-23
Fig. 4h is a perspective view of the cap element of the embodiment of Fig. 4,
showing the interior region.
Fig. 4i is a side elevation view of the container apparatus body of Fig. 4,
showing
the retention and anti-rotation elements.
S Fig. Sa is a top elevational view of another embodiment of the cap of the
container
apparatus according to the present invention.
Fig. Sb is a cross-sectional view of the cap of Fig. Sa, taken along Line Sb-
Sb.
Fig. S c is a detail view of the sidewall portion of the cap of Fig. Sb: .
Fig. Sd is detail view of the support feature of the cap of Fig. Sb.
Fig. 6a is a cross-sectional view off' yet another embodiment of the container
apparatus according to the present invention.
Fig. 6b is a top elevational view of the cap of the container apparatus of
Fig. 6.
Fig. 6c is a detail view of the cap and body thread region of the apparatus of
Fig. 6a.
Fig. 6d is a partial elevational view of the upper region of the container
body shown
1 S in Fig. 6a (cap removed), illustrating an exemplary body locking
mechanism.
Fig. 6e is a partial elevational view of the upper region of the container
body shown
in Fig. 6a (cap installed), illustrating the various interactions between the
body locking
mechanism of Fig. 6d and that locking mechanism (tab) of the cap.
Fig. 6f is a detail view of yet another embodiment of the cap and body thread
region
of the container apparatus of the invention, including a deformation-resisting
lip.
Fig. 7 is a logical flow diagram illustrating an exemplary embodiment of the
generalized method of manufacturing the container apparatus of the invention.
Detailed Description of the Invention
Reference is now made to the drawings wherein like numerals refer to like
parts
throughout. w
It is noted that while the invention is described herein primarily in terms of
apparatus and methods for use with animal species such as bears, the invention
may also be
readily embodied or adapted to other species and applications. All such
adaptations and
alternate embodiments are readily implemented by those of ordinary skill in
the relevant
arts, and are considered to fall within the scope of the claims appended
hereto..
As used herein, the term "animal" refers to any type of non-human,living being
or
organism, including without limitation members of the Ursa or bear family
(e.g., ursus
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CA 02482286 2004-09-23
ame~icahus or black bear, ursus horribilis or grizzly bear, and ursus
ma~itimus or polar
bear), as well as other species.
As used herein, the term "molded" or "molding" refers generally to a process
wherein
a material is formed to a desired shape or configuration before curing or
hardening. Molding
may include for example, injection molding, blow molding, or transfer molding,
or even other
types of forming processes.
As used herein, the terms "exclusion" and "resistant" refer generally to the
ability to
frustrate access to a protected volume for a period of time.
Overview
The present invention comprises improved apparatus and methods for selectively
permitting or restricting access to a container, such as is useful with
various animal species
including bears.
In one aspect, the invention comprises an improved container designed to
provide
I S all of the foregoing attributes (including light weight, low cost, ease of
use and carrying,
and climatic tolerance). while also presenting a virtually impenetrable
barrier to animals.
The exemplary embodiment comprises a highly resilient, lightweight, one piece
polymer
(polycarbonate) body or shell having a large-diameter aperture disposed at one
end. A
threaded, partially flexible lightweight polymer cap element mates with the
body; the cap
element comprises a tamper-resistant configuration with locking features which
prevent
rotation of the cap with respect to the body past a certain point. A ridge is
formed on the
body along the mating region of the cap, the ridge acting to prevent any
animal (or human
for that matter) from being able to insert anything (e.g., claws) under the
cap when installed
to pry it off. The locking features, ridge, body, and cap coordinate to make
the cap
sufficiently loose with respect to the body when installed so as to (i) absorb
flexing of the
body (such as under the weight of a bear standing on the side of the body),
and (ii) permit
passage of air between the interior and exterior of the body via the cap, yet
preclude the cap
from coming completely loose or exposing the underside of its outer rim to the
animal.
Hence, the exemplary container of the present invention is pliable enough to
distort without
opening, yet resilient and rugged enough to prevent permanent deformation,
fracture, or
cracking even under the weight (and motive forces) of a fully grown bear.
The container of the present invention is also advantageously equipped with
features which permit ready carrying by the user via straps or other
comparable means
without slippage, thereby enhancing the container's functionality and the
user's enjoyment.
-12-
CA 02482286 2004-09-23
Improved methods for manufacturing the aforementioned apparatus are also
disclosed. These methods are greatly simplified over the prior art (especially
those of the
Model 812 and Bearikade devices previously described), thereby allowing the
apparatus to
be produced at extremely Iow cost.
Exemplary Embodiments
Referring now to Figs. 3-3c, a first exemplary embodiment of the tamper-
resistant
container of the present invention is described in detail. It will be
recognized that while
these exemplary embodiments are designed primarily in the context of bear
exclusion, the
general attributes and principles may be particularly adapted to containers
for use with
other species, including even humans (e.g., small children).
A first exemplary embodiment of the container apparatus 300 is shown in Figs.
3-
3e. As shown in Fig. 3, the first exemplary embodiment 300 comprises a
substantially
cylindrical body element 302 onto which a matching cap element 304 is mated.
Specifically, the cap element 304 is threaded onto the body element 302 until
the desired
tightness is achieved. The body 302 is, in the- illustrated embodiment,
comprised of a
substantially translucent molded polycarbonate polymer (having a bluish hue)
nominally on
the order of 0.13 in. thick, although other materials (even including lighter
weight metals
such as aluminum alloys) and thickness values may be substituted. It is also
noted that the
thickness may vary over the range of different locations on the body 302; for
example, the
illustrated body is approximately 0.16 in. thick on the bottom and 0.13 in.
thick on the
sides. The opacity and coloration of the body material are completely
controllable using
well-known polymer techniques; hence, the body can be made to have literally
any degree
of opacity and any color (or mixture of colors, such as a camouflage pattern)
desired.
Polycarbonate is chosen for the body material of the illustrated embodiment
for,
inter alia, its (i) low cost, (ii) relative abundance; (iii) great mechanical
strength, including
endurance under a high number of flexural cycles, high yield strength, good
tensile and
compressive strength, fracturelshatter and impact resistance, and hardness;
(iv) flexibility,
and (v) desirable resistance to everyday chemicals to which the body 302 may
be exposed
including, e.g., water, cleaning solutions, toothpaste, soft drinks (having
carbonic acid),
acetic acid, alcohols and solvents, and any number of other substances: The
excellent
mechanical properties of polycarbonate allows the body 302 of the illustrated
embodiment
to be substantially thinner than might otherwise be achieved through use of
other materials
-13-
CA 02482286 2004-09-23
(such as ABS), thereby allowing for lighter weight. Poliycarbonates are well
known in the
polymer arts, and accordingly not described further herein.
The body 302 further comprises an aperture 306 formed in one end of the body,
over which the cap 304 fits. The aperture is nearly the full diameter of the
body 302 at the
tatter's widest point, thereby advantageously providing almost totally
unimpeded ingress
and egress from the interior volume 307 of the body 302 by the user.
The body 302 also includes a plurality of molded threads 308 (see Fig. 3b)
formed
along the outer periphery of the cap receiving portion 310 of the body 302.
These threads
308 are matched in pitch and taper to corresponding threads 312 formed on the
interior
surface 313 of the ring portion 314 of the cap 304. The threads 308, 312 of
the illustrated
embodiment are disposed in "right hand" configuration such that tightening
occurs when
turning the cap relative to the body in a normal clockwise motion, although it
will be
appreciated that a counter-clockwise or reverse thread configuration may be
utilized
consistent with the invention, such as for making the apparatus more child-
proof.
IS Also disposed proximate the threads 308 of the body 302 is a guard ridge
316 (see
Figs. 3b and 3c) which, in the illustrated embodiment, is molded into the body
302. This
ridge is, disposed proximate to the base plane 317 of the threads 308, and
projects
substantially upward (i.e., in a direction substantially parallel to the plane
of the threads 308
and the cap receiving portion 310. This ridge 316 advantageously blocks access
to the
underside of the cap sidewall 3I8, since the bear (or other animal) cannot get
its claws
anywhere near the cap sidewall edge, when the cap 304 is installed on the body
302. The
clearances and height of the exemplary ridge 316 are such that even if the cap
304 is not
fully tightened, access to the cap-body gap 319 is completely frustrated.
Hence, when
assembled, the cap 304 and body 304 (and ridge 316) cooperate to form a
substantially
even, uniform outer surface with an extremely minimal, unexposed gap between
the
components. This cap/ridge relationship is also significant in light of the
locking features
320, described in greater detail subsequently herein.
The thickness of the polycarbonate body molding varies somewhat over its area
such that different portions as a whole are somewhat easier to flex than
others. This is
particularly true of the top portion of the body 302 near the threads 308, due
in part to the
presence of the aperture 306.
As shown in Fig. 3a, the bottom portion 330 of the body is formed with a
highly
rounded interface 332 between the side wall 334 and the bottom face 335 (the
latter being
indented by approximately 0.1 in. in the illustrated embodiment to present
only an annular
_ 14- .
CA 02482286 2004-09-23
or toroidal contact area, to prevent the "pinchoff ' region of the molding
from interfering
with the stability of the container, and to provide greater stability to the
container 300 when
placed on an uneven surface potentially having "clutter" such as small rocks
and the like).
The rounded interfaces 332 advantageously preclude the bear or other animal
from getting
its jaws solidly locked onto the container 300, or cracking this particular
area of the body
molding. It is noted that some larger bears may be able to get the entirety of
the diameter
of the body 302 within their jaws; however, testing performed by the inventor
hereof on
actual bears (zoo) has indicated that even large bears lack sufficient jaw
strength to crack or
collapse the high-strength polycarbonate body. The exemplary embodiment of
Fig. 3 also
avoids the use of any extended ridges or features (with the exception of the
gap-protecting
ridge 316) so as to frustrate attempts by the animal to catch its teeth on
such features,
thereby providing additional biting leverage. The hardness and relative
smoothness of the
polycarbonate molding also frustrate such attempts, since the animal's teeth
cannot
significantly penetrate the polycarbonate to any sufficient depth, and merely
slide off.
I5 The aap element 304 also comprises a one-piece molding; however, glass
reinforced
nylon is selected for this component so as to match the thermal expansion
properties of the
polycarbonate container to prevent the lid from seizing onto the container in
cold weather
and to provide sufficient strength, yet with very low weight and flexibility
and
chemical/substance resistance. It will be appreciated, however, that other
types of material
(including bath other variants of nylon, and other polymers or mixtures
thereof) may be
substituted with equal success. The present embodiment utilizes a glass
reinforced nylon
molding of approximately 0.120 in. nominal thickness at its center to provide
the desired
mix of rigidity and flexibility (described in greater detail below); however,
other thickness
values may be used.
Locking features (elements).320a, 320b are also provided on both the body 302
and
cap 304 of the illustrated embodiment to effect animal exclusion, yet permit
the user ready
access. in contrast to the more complicated, costly, and difficult to operate
locking
mechanisms of the prior art previously solutions descrilbed herein, the
locking features 320
of the present invention are ultra-low cost, ultra-light weight, and require
no tools or coins
to operate. Specifically, the locking elements 320 comprise complementary
raised bumps
(here, substantially hemispherical shapes) disposed in relative opposition to
each other, one
on the cap element 304, one on the body element 302. In the illustrated
embodiment, the
locking elements 320 are each molded as part of their parent structure (i.e.,
cap 304 or body
302), although other arrangements including bonding via adhesives or the like
may be
-1 S-
CA 02482286 2004-09-23
substituted. The molding of the elements 320 into them parent structures
reduces cost by
obviating additional labor steps, and increases rigidity in that the elements
320 are integral
with the molecular structure of the parent device.
The locking elements 320a, 320b (Fig. 3c) are disposed on the cap 304 and body
302 respectively at an elevation and position such that the two elements 320
engage one
another when the cap 304 is partly screwed onto the body 302, with sufficient
threaded
engagement to preclude easy cap removal. Specifically, the locking elements
320 are
designed to engage when the cap is approximately 2/3 through its full
rotational travel,
thereby placing the lower edge of the cap sidewall 318 well below the
elevation of the body,
ridge 318. Hence, when the cap 304 is not fully screwed on, the inter-cap gap
319 is not
exposed to the animal. When the two locking elements 320a, 320b do engage, the
user
simply distorts the cap sufficiently (and concurrently applies torque to the
cap in the
rotational direction) so as to cause the one element 320a to move past the
other element
320b. This (albeit minimal) distortion is accomplished simply through grasping
the cap in
one's hands, the nylon material being sufficiently pliable to flex enough to
move the two
elements 320a, 320b relative to one another in the radial dimension, somewhat
akin to the
well-known "child-proof cap" on pharmaceutical bottles.
Herein lies a salient advantage of the present invention; i.e., that once the
two
locking elements 320 are past one another (i.e., the cap is tightened
sufficiently such that
the cap element 320a has proceeded beyond the body element 320b), the cap 304
can be
left in this position, i.e., not completely tightened, and it is none-the-less
fully animal-proof.
This feature is accomplished through coordination of the locking elements 320
(and their
placement), the cap 304, threads 308, 312, and the ridge 316. This
functionality is
particularly useful when malting significant altitude changes; the user merely
does not
screw the cap down tight, which permits at least some passage of air over the
threads, and
prevents a significant differential pressure from building up and potentially
creating a
"vacuum" lock on the cap 304, thereby making it difficult to open. Small
pressure
equalization holes can also be provided .if desired; however, these allow
odors (e.g., food)
resident within the container volume to interchange with the outside air,
thereby potentially
attracting animals and potentially inciting attack thereby if the user is
carrying the container
300.
It will further be recognized that while the illustrated embodixiient shows
one pair of
locking elements 320a, 320b, multiple sets may be used. For example, a first
and second
set could be disposed at slightly different azimuths along the periphery of
the.body upper
-16-
CA 02482286 2004-09-23
portion 310 and cap 304, such that multiple manipulations and distortions are
required to
install or remove the cap 304. This would also potentially act as insurance
against the bear
getting "lucky" and potentially exerting the right combination of forces and
motion to
rotate the cap 304 past the first set of locking elements 320; the bear would
in fact have to
get lucky twice (or more times when added sets of locking elements are used)
to get the cap
off the container body.
Alternatively, two sets of locking elements can be disposed diametrically
opposed
to one another (i.e., pi radians away from each other), such that a doubling
of the force
normally necessary to overcome the interference between one set of elements
320 is
achieved. Myriad other variations along the foregoing themes are possible
consistent with
the invention, as will be appreciated by those of ordinary skill in the
mechanical arts.
In use, the locking features 320, ridge 316, body 302, and cap 304 coordinate
to
make the cap element 304 sufficiently pliable with respect to the body 302
when installed
so as to (i) absorb flexing of the body (such as under the weight of a bear
standing on the
side of the body), and (ii) permit passage of air between the interior and
exterior of the
body via the cap, yet preclude the cap 304 from coming completely loose or
exposing the
underside of its outer rim to the animal. Hence, the exemplary container of
the present
invention is advantageously flexible enough to distort without opening, yet
resilient and
rugged enough to prevent permanent deformation, fracture, ox cracking. The
polycarbonate
body 302 and Glass reinforced nylon cap 304 coordinate to absorb and dissipate
the
mechanical force applied by the animal through controlled flexing of these
components,
thereby rendering the container highly resistant to both slowly applied forces
and more
impulsive transients.
It is significant to note that, in contrast to the prior art (such as the
Model 812
device), the cap 304 of the present embodiment does not form a significant
compressive
structural member for the body 302. As previously described, the Model 812
device uses
the relative incompressibility of the cover plate in the transverse direction
to bolster the
canister body in the region of the access aperture: Hence, the cover of the
Model 812 is
placed under compressive loading when transverse loads are applied to the
canister body.
Contrast this with the embodiment of Fig. 3, wherein the cap 304 in no way is
exposed to
compressive load (and actually may be exposed to some tension loading) when
the body
302 is compressed transversely.
The foregoing cap/ridge/body arrangement also advantageously helps prevent
moisture intrusion within the container volume; the small gap 319, ridge 316,
and threads
-17-
CA 02482286 2004-09-23
- 308, 312 coordinate to make the container 300 highly moisture resistant,
even when the
container is submerged in moderate depths of water (assuming the cap 302 is
tightened
down). The outside pressure of the water during submergence also helps to seal
the cap
against the inner radial portion 350 of the body 302 {i.e., the annulus
directly behind the
ridge 316), as well as other portions of the body, thereby effectively
mitigating further
water intrusion.
The foregoing cap/ridge/body arrangement also advantageously prevents the
intrusion of rain or other incidental moisture into the container (regardless
of container
attitude) due to the overlapping nature of the lid and threads, a feature
which the prior art
Model 812 fails to provide.
As shown best in Fig. 3, the body 302 also optionally contains a plurality of
retention elements 330 disposed on the outer surface of the body 302. In the
illustrated
embodiment, these elements 330 comprise a plurality molded-in "ridges" of
approximately
0.064 in height disposed in two parallel rows extending around at least a
portion of the
circumference of the outer surface of the body sidewall. These rows are offset
by a given
amount from each other (nominally 1.28 in.) corresponding roughly to the width
of a
standard restraining strap. Two sets of rows are provided; a first 333 near
one end of the
body 302, a second 334 near the other (cap) end of the body. In operation,
these elements
330 act to prevent restraining straps affixed by the user and disposed between
the rows (of
each set) from moving of sliding longitudinally along the body 302 during user
movement.
The present embodiment uses rounded-cross-section ridges (versus other shapes)
to both
provide good restraint and minimize the opportunities for the animal catching
its teeth on
the elements and potentially gaining additional leverage as previously
discussed (i:e.,
maintaining a smooth and largely featureless outer presentation). However,
such rounded
cross-section is not an essential feature, since the polycarbonate body 302 is
sufficiently
robust to withstand biting pressure even if the animal can get a firm bite on
the body, via
any surface features. While ridges are shown, 'it will be appreciated that
many other
configurations of these retention elements 330 may be used in substitution or
in concert,
including e.g., a series of raised bumps, punctuated set of ridges, rough
texture patches,
molded-in channels or depressed legions, and the like.
In another embodiment (Fig. 3e), the retention elements 370 comprise two or
more
molded "loops" having an aperture 372 formed therein for receiving a
restraining strap (not
shown). These loops have the advantage of more securely capturing the
restraining
strap(s), and also frustrating uncontrolled rolling of the cylindrical
container 300 down an
-18-
CA 02482286 2004-09-23
-. incline (the loops 370 act as rotation stops). However, the loops 370 also
present a better
opportunity fox the animal to latch its teeth or claws onto the container.
Yet, even if
exposed to force sufficient to fracture the loop 370, the properties of the
polycarbonate and
design are such that the loop only will fracture, and not cause any
significant damage to the
body 302 of the container. This feature maintains the structural integrity of
the container
while providing the benefits (i.e., better restraint and anti-roll protection)
previously
described.
The container 300 of Fig. 3 may also be textured on its surfaces if desired.
For
example, in one exemplary variant (not shown), a semi-rough surface texture is
applied
over a substantial portion of the outer surfaces of the body 302 (such as by
using an acid
etch process of the type well known in the polymer molding arts on the mold
used to make
the body), thereby providing reduced slippage in the hands of the user, as
well as some
degree of opacity. External texturing may also reduce tl~e ease with which the
aesthetics of
the container 300 are degraded, such as by making it mare scratch resistant
(or at least
making any scratches or damage that does occur less noticeable).
Similarly, if it is desired to keep the outer surfaces smooth (to mitigate
animal tooth
or claw friction), the texture can be applied to the interior surfaces of the
body. One
potential benefit of such texturing is the reduced visual feedback provided to
the offending
animal; a bear which sees an apple in the container 300 is probably more
likely to persist in
its efforts as compared to one which does not. Similarly, other types. of
coatings can be
applied to the inner and/or outer surfaces of the container body 302, such as
for example a
mirrored or white reflective coating to mitigate solar or radiant heating of
the contents of .
the container. Such coatings may comprise for example the functional
equivalent of shelf
paper, which is low cost, Iow weight, adherent to the relevant surface, or
even be entrained
, within the polymer body itself in the form of inclusions, etc.
The benefits of the container 300 of Fig. 3 cyan also be quantified in terms
of
commonly used metrics; i.e., capacity and weight. rapacity is typically
measured in
person-days of supplies. Weight is measured in any appropriate unit (e.g.,
pounds or kg).
Hence, one can form a useful measure of the spatial efficiency of a container
by ratioing
these two quantities; i.e., capacity/weight. A higher weight and lover
capacity device will
produce a lower spatial efficiency index (SEI). The inventor hereof has
measured the most
commercially popular prior art solution (Model 812), and found it to have a
weight of 2
lbs., 12 oz. (approximately 1250 grams, or 1.25 kg). It is advertised as
having a 6-person
day capacity. Hence, the SEI for this device is 6/1.25 = 4.80. In contrast,
the exemplary
-19-
CA 02482286 2004-09-23
- embodiment of Fig. 3 (manufactured by the inventor hereof as of the date of
this,filing) has
an SEI of 711.11 = 6.3I . The present invention therefore provides clearly
improved storage
capacity per unit of container weight (approximately a 31 % improvement on the
basis of
the SEI metric) over the Model 812 device.
When considering the smallest Bearikade model (6-person days at 1 lb, 15 oz.),
the
SEI of the Bearikade is higher thann that of the exemplary embodiment analyzed
above (i.e.,
6.82 versus 6.31, the former roughly 8% higher). However, similar metrics must
also be
applied in terms of cost; e.g., cost per unit of capacity, etc. Owing to its
lower
manufacturing cost, the present invention compares very favorably to both of
the prior art
solutions described above when cost as well as SEI is considered. The
referenced Bearikade
model costs more than twice that of the exemplary embodiment of the present
invention,
with only 8% better SEI, while the Model 812 device has both higher cost and
lower SEI.
Referring now to Figs. 4-4i, a second exemplary embodiment of the container
apparatus is described. In this embodiment, the apparatus 400 comprises a body
402 and
1 S cap 404 generally similar to that of Fig. 3; yet the cap 404 comprises a
two-piece assembly
adapted to provide a safety or exclusion function. Specifically, the
illustrated cap 404
includes an outer cap element 440 and a corresponding interior ring structure
442, the two
components 440, 442 cooperating permit substantially unimpeded rotation of the
cap
element 440 with respect to the ring unless a downward (normal) force is
applied. Hence,
the cap assembly 404 functions much like a child safety top on a
pharmaceutical bottle.
Figs. 4b and 4d-4h illustrate the details of these components 440, 442. As
shown in the
Figures, the ring structure 442 is adapted to fit within the interior portion
of the cap element
440, and slide selectively therein. The interior surface 445 of the cap
element 440 (Figs. 4g-
4h) includes a plurality of raised features 446 which project normally from
the surface 445.
The height of these features 446 is controlled such that there is just enough
friction between
them and corresponding ones of groove elements 447 (Figs. 4d-4fj formed in the
top
surface of the ring structure 442. While the raised features 446 are
substantially symmetric,
the groove elements 447 are purposely rriade asymmetric (i.e., one edge 448 of
each groove
447 is tapered from vertical so as to frustrate meaningful frictional contact
with a .
corresponding edge of a raised element 446 of the cap 440. Hence, the cap
element 440
and ring structure 442 are polarized in one direction; rotation of the cap
element 440
relative to the ring structure 442 (and hence the container body 402) in a
clockwise
direction allows two substantially vertical edges (one on the raised element
446, one on the
corresponding groove element 447) to positively engage, thereby allowing the
user to
-20-
CA 02482286 2004-09-23
- tighten the cap assembly 404 onto the body 402. Each pair of raised elements
446 and
groove elements 447 also engages in similar manner.
However, when rotating the cap element 440 .in the counter-clockwise direction
(loosen direction for right-hand threads); the aforementioned tapered edge of
each groove
element engages a corresponding (substantially vertical) edge of each raised
element 446,
with the result that the two components 440, 442 do not positively lock
together and slide
in relation to one another unless an appreciable downward force (on the order
of 10 pounds
or 10_ lbfj is applied to the cap element 440 during rotation. This downward
force allows
sufficient frictional coupling between the two elements 446, 447 (and others
along the
periphery of the cap/ring structure) to overcome the frictional counter force
generated by
the mating of the two sets of threads 408, 412 on the inner surface of the
ring structure 442
and the outer surface of the body 402, respectively. If insufficient downward
force is
applied, the two components 440, 442 slip, and the ring structure 442 remains
unmoved
while the cap element 440 merely rotates over it.
1 S The cap element 440 is retained relative to the ring structure 442 by way
of a lip or
recess 452 farmed on the interior surface of the cap element vertical sidewall
450, as shown
best in Figs. 4b, 4g and 4h. Since the polycarbonate body 402 is substantially
rigid, and the
ring structure 442 tightly engages the thread portion of the body 402, the
ring structure is
very firmly supported against inward deflection. Similarly, since the ring
structure is
received within the recess 452 of the cap element 440, the latter being
resistant to outward
deflection or spreading, the ring structure 442 is also firmly supported
against outward
deflection or disengagement of the threads 408, 412. Hence, the recess 452 is
sufficient to
keep the ring structure 442 firmly captured within the cap element 440 under
all operational
conditions and loadings. This is especially true when considering the presence
of the ridge
416 formed on the body 402 proximate to the bottom edge of the 'cap element
440;
specifically, the animal can exert no significant shear or upward force on the
cap element
(so as to separate the cap element 440 from the ring structure 442 and body
402), since it
cannot get any portion of its claws or teeth into the gap 419. The cap element
440 is also
made quite low in vertical profile (less than one inch), thereby affording the
animal very
little of a comparatively slick surface to grasp onto.
The embodiment of Fig. 4 utilizes a Glass reinforced nylon cap element 440
similar
to that of the embodiment of Fig. 3; however, the ring structure 442 is formed
(molded) of a
low-friction polypropylene polymer of the type well k.~aown in the art. This
latter material
is chosen for low cost and good mechanical properties including sufficient
strength and low
-21-
CA 02482286 2004-09-23
friction. It will be appreciated, however, that other materials (polymer or
otherwise) may
conceivably be ,substituted. For example, fluorinated polymers such as
ethylene tetra-
fluoroethylene or ETFE (Tefzel~) or Teflon ~ may be used, such fluoropolymers
having
excellent friction resistance and chemical/mechanical properties (albeit at
somewhat higher
typical cost than glass reinforced nylon or comparable materials). Similarly,
the ring
structure 442 can be made from Glass reinforced nylon. Myriad othex options
are available.
It will also be appreciated that the foregoing locking mechanisms (i.e., the
locking
elements 320 of the embodiment of Fig. 3, and the "safety cap" mechanism of
the
embodiment of Fig. 4) can be combined if desired, in order to provide an extra
level of
protection. For example, the locking elements 320 of Fig. 3 can be utilized
a~s a secondary
lock or backup to the safety cap of Fig. 4, the former being positioned such
that after the
thread friction of the ring structure 442 is overcome, the user must then
distort of deflect
the cap element 440 such that the two locking elements 320 can slide past one
another as
previously described with reference to Fig. 3:
As shown in Fig. 4i, the illustrated embodiment also includes a plurality, of
retention
ridges 460 having generally similar functionality to the retention elements
330 of the
embodiment of Fig. 3. A set of complementary anti-rotation features 466 are
also disposed
proximate to the base 470 of the body 402. In the illustrated embodiment,
these anti-
rotation features 466 comprise ridges which are vertically oriented or
substantially parallel
to the longitudinal axis of the container 400. These features 466 are utilized
to, inter alia,
provide friction to a user attempting to hold the body 402 steady while
rotating the cap.
Specifically, the user straddles the container 400 and places the features 466
(one set each
disposed diametrically opposed to the other proximate the base 470) in contact
with the
interior surfaces of their shoes/boots; the features 466 engage.the user's
shoes/boots and
mitigate rotation of the body while screwing or unscrewing the cap assembly
404. While
ridges are shown, it will be appreciated that many other configurations of
these features 466
may be used in substitution or in concert, including e.g., a series of raised
bumps, rough
texture patches, and flattened regions formed in the base area 470 or
projecting out
underneath the container.
It will be recognized that while two exemplary embodiments of locking
mechanisms and cap structures have been described explicitly herein (i.e.,
those of_Figs. 3
and 4), numerous other cap/locking mechanism configurations can be used
consistent with
the invention to provide similar benefits and functionality. For example; the
container cap
may be configured such that the user must depress one or more tabs disposed on
the
-22-
CA 02482286 2004-09-23
periphery of the cap (not shown) in a radial direction (i.e., inward or
outward) to permit the
engagement of the cap to the ring structure. As yet another alternative, the
cap/body may be
configured such that combinations of motions (e.g., downward force and radial
pressure)
are required. AlI such variations will be readily recognized by .those of
ordinary skill
provided the present disclosure, and are considered to fall within the scope
of the claims
appended hereto.
Another feature afforded by the low cost of the container apparatus described
herein
relates to its disposability; while a camper or hiker m.ay think twice about
letting a bear
steal away with a higher cost container (e.g., graphite epoxy Bearikade), the
cost penalty
provided by loss of the container of the present invention is quite low.
Hence, the present
apparatus provides the user with added safety and freedom, in that loss of the
apparatus is
financially inconsequential, and the user will not be tempted to undertake ill-
advised
attempts at recovering the container (perhaps to their ovm detriment or that
of the bear).
Referring now to Figs. Sa-5d, another embodiment of the container apparatus of
the
invention is described in detail. The container apparatus of this embodiment
is generally
similar in .form to that previously described herein (e.g., the container 300
of Fig. 3), yet
includes additional or alternate features that make the lid (cap) 504 even
more difficult to
remove inadvertently or unintentionally. In this embodiment, the, cap 504
comprises a
single piece unit adapted to cooperate with the housing tabs) 320b (see Figs.
3c and 3d).
Specifically, the tabs 320b and the outer surface 520 of the cap 504 are
positioned relative
to one another such that the outward (i.e., radial) travel of the cap walls
522 is substantially
frustrated. For example, in the exemplary embodiment, the height of the
complementary
threads on the lid and the housing are on the order of 0.085 in. (see Fig.
3c). Hence, for the
cap 504 to move longitudinally with respect to the body 302 (without being
threaded on or
2S off), the cap wall 522. must move roughly 0.085 in. outward ox radially
from the threads on
the body 302, such that the threads of the cap and body are substantially
clear of one
another.
While under normal use conditions, such relative movement is extremely
unlikely,
it is conceivable that extreme use conditions may cause such a movement. For
example, if
an object of sufficient mass and density (such as an aluminum or steel
beverage can full of
liquid) is present within the interior volume of the body 302 and can travel
unimpeded,
sufficient acceleration of the object in a direction normal to the top surface
of the cap 504
could potentially dislodge the cap 504 from the body by hitting the interior
of the cap with
sufficient energy during movement. Even a sharp impact of sufficient force on
the outer
-23-
CA 02482286 2004-09-23
w top surface of the cap 504 may cause sufficient deflection or distortion of
the cap to allow it
to be dislodged. The cap 504 may also be "pre-loaded" or made more likely to
fail in this
manner due to other conditions, such as over-filling or stuffing of the body
302 by the user
(thereby biasing the cap outward due to pressure on its inner top surface), or
under extreme
thermal environments where the differential thermal expansion coefficients of
the cap and
body cause the body to shrink somewhat in diameter relative to the cap (or
alternatively the
cap to expand somewhat relative to the body). .In this fashion, less force
would be required
to dislodge the cap-than under nominal operating conditions.
Hence, the embodiment of Figs. 5a-5d frustrates such undesired or
unintentional
dislodging or removal of the cap 504 from the body 302 by limiting the outward
(radial)
travel of the cap sidewall 522 under all operating conditions to an amount
significantly less
than that required to dislodge the cap 504. For example, in the above.-
referenced
configuration, the distance between the outer surface of the cap sidewall and
the innermost
surface of the tabs) 320b is on the order of 0.03 in., far less than the
required 0.085 in.
required for relative movement of the threads over one another. This
arrangement
advantageously allows the cap 504 to be threaded onto the container body 502
with little or
no interference between the cap and tab (except when the locl~ing mechanism
tab on the
housing is interacting with the locking mechanism on the cap 504), and allows
sufficient
distortion of the cap 504 to occur to permit actuation of the aforementioned
locking
mechanism(s), yet completely frustrates inadvertent cap removal under all
operating
conditions (up to the yield or breaking point of the cap or body materials).
It will also be appreciated that various types of locking mechanisms can be
utilized
with the configuration of Figs. 5a-5d. For example, the cap 504 may include
one or more
locking features around its periphery. These features may comprise tabs 320a
such as those
of the embodiment of Fig. 3, or alternatively substantially vertical channels
530 formed into
the outer surface 520 of the cap 502 (shown in Fig. 5a), with the tabs 320b on
the housing
engaging the channels 530 and accordingly providing resistance to rotation.
The features
may alternatively comprise raised shapes (e.g. vertical "bars") which can
interact with the
housing tabs) 320b much as the tabs) 320a of the cap of Fig. 3 do. These
features also can
provide the user with a better grip on the cap when threading it on and. off,
yet are
insignificant enough in size to provide no advantage or leverage to a bear or
other animal
trying to gain access to the container.
Furthermore, the numbers of tabs 320a, 320b or channels, etc. used on the cap
and
housing can be varied as desired. For example, one housing tab 320b and one
cap tab 320a
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CA 02482286 2004-09-23
may be used. Alternatively, two housing tabs 320b can be disposed at 180
degrees from
one another around the periphery of the housing to limit the radial travel of
the cap sidewall
522 at both locations. This approach can be used with one, two, or more
locking tabs 320a
or channels 530 formed on the cap 504. It will appreciated that numerous such
variations
can be employed, depending on the desired attributes of the container (i.e.,
the degree of
effort required to open the lid, its level of resistance to impulse or
transverse force, etc.).
As shown best in Figs. Sb and Sd, the lid 504 also optionally utilizes a
strengthening
member 540 formed on the interior surface 542 thereof In the illustrated
ernbodirnent, a
molded-in ring or rim is utilized for simplicity, low cosrt, and high
strength, although it will
be appreciated that other configurations may be used, such as for example a
punctuated
series of bumps or posts, a solid structure (e.g., a mesa-like plateau), or
even elements
which are tapered to deflect somewhat inward in a radial direction during cap
tightening,
thereby in effect preloading or biasing the interior surfaces of the housing
thread region
outward somewhat. Myriad different configurations will be recognized by those
of ordinary
skill when provided with the present disclosure.
The molded ring 540 is formed on the cap 504. so as to coincide with and fit
just
within the interior surface of the housing thread area 308 (see Fig. 3b) so
that the ring 540
supports the thread region 308 from significant distortion under transverse
load such as that
imposed by a large bear jumping up and down on the side surfaces of the
container with its
front paws. As previously described, some degree of flex of the housing is
inherent under
such loading; and the cap described in prior embodiments is adapted to absorb
a certain
degree of this flexing. However, under extreme loading, the cap (without the
strengthening
member 540) deforms sufficiently to allow it to be unintentionally removed
("pop off ').
Hence, the cap 504 of the embodiment of Figs. Sa-Sc with its strengthening
member 540
provides additional support to the thread region 308 of the housing 302,
thereby mitigating
the degree of flex encountered.
The degree of support and rigidity provided by the ring 540 can be controlled
by,
inter alia, adjusting the gap between the outer periphery of the ring S40 and
the inner
surface of the threads 308, and/or adjusting the height, thickness and profile
of the ring 540
relative to the interior surface of the thread' region 308. For example, a
low, tapered bead or
ring 540 displaced inward from the thread inner surface would provide less
support and
allow greater flex than one having a greater height and width, more angular
profile, and
being disposed immediately adjacent to the inner surface of the thread region
308. Fig. Sd
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CA 02482286 2004-09-23
- illustrates one exemplary profile of the rim 540, having a generally flat or
vertical outer
wall 555 and angled or tapered inner wall 556.
In another variant (not shown), the cap 504 (or i:or that matter the cap of
any of the
embodiments described herein or others) can be fitted with an energy
dissipation element
which helps mitigate the energy transfer (impulse) between the object and the
interior
surface of the cap 504. For example, in one embodiment, an ultra-lightweight
foam rubber
insert is disposed on the interior of the cap 504, such as in a substantially
hemispherical
shape with a diameter less than the inner diameter of the mouth or opening of
the body 302
and centered on the cap top interior surface to avoid any interference between
the insert and
the body 302. Hence, when the cap is threaded onto the body, the insert is
disposed
squarely within the mouth of the body, hemispherical side facing the interior
volume of the
body 302.
When the aforementioned object accelerates toward and strikes the insert, the
foam
rubber construction of the insert absorbs a significant fraction of the
object's energy (via
compression of the foam matrix cells within the insert), and also distributes
the energy to a
larger surface area of the cap interior due in significant part to the
structure of the foam and
the hemispherical shape of the insert. Accordingly, the same object must have
greater
initial energy to dislodge a cap with the foam insert than one without, and
the foam insert
advantageously adds very little to the weight and cost o~f the container
apparatus. The foam
insert can be mated to the cap in any number of ways, such as using adhesives,
thermal
bonding, or even mechanical retention means (such as lip or rim formed on the
interior of
the cap under which a peripheral portion of the insert is captured, which may
even comprise
the ring of Figs. Sb {or Fig. 6a described subsequently herein). Furthermore,
other
materials and configurations of insert element may be used, such as for
example a
substantially cylindrical shape of a polymer having' a progressive or non-
linear compression
profile, a "gel" element, etc. Note that the interior of the cap can even be
molded with one
or more energy dissipating structure, such as a frustoconic section or the
like designed to
distribute the impact energy of the object to the body 302 or other
components. Myriad
other variations will be appreciated by those of ordinary skill given the
present disclosure.
Referring now to Figs. 6a-6e, yet another embodiment of the cantainer
apparatus of
the present invention is described. As shown in Fig. 6a, the apparatus 600
comprises a body
602 with thread area 608 adapted to receive a cap 604. The cap 604 and body
602 are
generally similar to those previously described herein, yet with several
distinguishing
features as will now be described in greater detail.
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CA 02482286 2004-09-23
- Fig. 6b shows the cap 604 of the apparatus 6~0. The apparatus 600 includes
locking
mechanism comprises two corresponding cap and housing tabs 620a, 620b which
are
generally in the shape of non-equilateral triangles (see Figs. 6d and 6e).
Each triangular tab
includes an engagement surface 650 which is disposed at an angle of
approximately 20
degrees relative to a radial or normal vector from the central axis of the
housing, although it
will be appreciated that other angles and shapes may be used. The angles of
each tab 620a,
620b are reversed from one another as shown so that l:he engagement surfaces
650 of the
two tabs 620a, 620b mate when the cap 604 is being unthreaded (removed) from
the body
602. This mating or engagement frustrates further rotation of the cap 604. The
use of
opposed angled engagement surfaces 650 advantageously tends to make this
locking
mechanism even more resistant to tampering or unintended removal of the cap
604 by
seating the two tabs 620x, 620b against each other in an increasing positive
engagement as
more counter-rotation (e.g., CCW) force is applied to the cap 604.
The thread area 608 of the body 602 also contains one or more cutouts 652 or
recesses immediately proximate and just inboard to the tab 620b on the housing
(see Fig.
6d). This cutout allows the sidewall of the cap 604 on which the cap tab 620a
is mounted to
flex inward or deform somewhat in that region, such as when pressed on in a
radial
(inward) . direction by the user's thumb or forefinger (see Fig. 6e). This
deflection or
deformation allows the two tabs 620a, 620b to move past one another just
enough to
unscrew the cap 604.
In the illustrated embodiment, the vertical placement of the cap tab 620a on
the
sidewall of the cap 604 is selected such that it is sufficiently below the
plane of the lowest
threads on the interior sidewall of the cap, thereby leaving the sidewall
portion below the
threads (i.e., with the tab 620a) to flex inward past the outward-most radial
extension of the
threads on the body 602. Stated differently, the tab 620a is placed low enough
on the
sidewall of the cap 604 that it can deflect inward far enough, and the threads
of the body
602 don't significantly interfere with the inward travel. Fig. 6c illustrates
the extension of
the cap sidewall 622 below the plane of the lowest threads of the cap 604 or
body 602.
The exemplary body 602 of Fig. 6a is also optionally reinforced with one or
more
"ribs" 660 formed within the body that advantageously stiffen the housing,
especially to
transverse loading. These ribs 660 rnay be extended over less or more of the
length of the
body 602 as desired, and also may be spaced differently (or even utilize
heterogeneous rib
depth, width and/or spacing) to provide the desired physical characteristics
for a given
application. In the illustrated embodiment, the central portion 664 of the
body (which
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CA 02482286 2004-09-23
includes the ribs 660) is optional via a removable mold section which allows
the mold to be
varied in length (i.e., either with or without the central portion 664). This
allows the use of .
the same mold for a full-length version (Fig. 6a) and a shortened length
version of the
apparatus (e.g., a 7-day capacity versus a 4-day capacity).
The cap 604 of the illustrated embodiment also optionally includes an interior
support feature 640 (e.g. ring) as in the embodiment of Figs. Sa-Sd discussed
'above (see
Fig. 6a). This feature adds further rigidity and resistance to unwanted cap
removal or pop-
off, as previously described: Specifically, for the cap 604 to pop off, the
cap's threads must
ride up and over the threads of the body 602. Either the cap 604 or the body
602 must
deflect by at least the height of the threads (e.g., 0.1 in. in the:
illustrated embodiment) in
order to allow the threads to ride up and over each other, and thus for the
lid to pop off.
However, the inner ring 640 on the cap is located just inside the inner
surface of the body
thread region 608 (e.g., 0.03 in. in this embodiment), so that as the cap/body
deflect, they
come in contact at the outer surface of the ring 640 and then cannot move
further relative to
each other (in the radial direction). This accordingly prevents the cap 604
from riding up
and over the body threads.
The exemplary cap 604 and body 602 of Figs. 6a-6e also optionally utilize
comparatively steep angles ("acme") threads to minimize friction when screwing
the cap
604 onloff. Similarly, the cap 604 may be fashioned from a low friction
plastic or other
material in order to allow it to easily screw/unscrew on the body's threads
608 without
binding up.
The aforementioned acme (i.e., steeper pitch) threads also provide another
benefit
relating to resistance to downward force. Specifically, when less steep
threads are used, a
person sitting on the cap 604 when it is partially unthreaded (i.e., with the
apparatus 600
sitting uptight on the ground) can cause the cap to "skip" one or more threads
due to the
downward pressure. This can result in a cross-thread situation where it
becomes very
difficult to subsequently free the cap. The use of steeper threads, as well as
other features
such as the shape of the body 602 and associated tab 620b which retains the
cap sidewall
substantially engaged against the threads as previously described, helps
prevent the cap
threads from riding over the body threads in such situations.
Referring now to Fig. 6f, yet another embodiment of the container apparatus of
the
invention is described. In this embodiment, a configuration similar to that of
Figs. 6a-6e is
utilized, yet with the addition of a deflection-mitigating lip 670 formed at
the base of the
housing threads 608 that is about 0.02" in vertical ~h.eight in the
illustrated embodiment.
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CA 02482286 2004-09-23
- This lip 670 has a diameter less than that of the inside of the cap 604 in
that region (e.g.,
0.04 in. less); so it will support the cap's lower edges from deflecting if a
bear claw
attempts to push these edges in to get under the cap 604. The fully threaded
(closed) cap
has this small lip 670 keeping the cap edge from deflecting inward as
discussed; however,
as soon as the cap 604 is loosened a bit (e.g., roughly one rotation), the
pitch of the threads
raises the cap 604 relative to the lip 670, pulling the lower cap edge away
from the lip 670
(the lip purposely has a very small vertical height for this reason). This
allows the lid to
deflect inward at the housing recess 652 as previously described (e.g., with
inward finger
pressure) since the lip 670 is no longer under the cap edge. Hence, this
support feature
provided by the lip 670 is only present in the very last .portion of the
travel of the cap 604
during tightening.
It will also be appreciated that the various features of the individual
embodiments of
the container apparatus described above may be used in combination if desired,
such as for
example, where the cap locking features of the embodiment of Figs. 6a-6e are
used together
with the cap sidewall restriction features of the embodiment of Figs. Sa-Sd,
and so forth.
Hence, the container apparatus can be customized during manufacture to the
particular
applications and/or users for which ~it is intended. This is particularly true
since many of
these optional features comprise relatively minor ch~u~ges to the molded body
and cap
components. To this end, a manufacturer. may maintain a set of different molds
and hence
components, from which the desired combination of features and components may
be
selected. These features can be offered, for example, according to a
differential cost
structure, such that a "baseline" model is priced lower than one with added
cap retention,
etc. features. In that the manufacture and assembly of these different
variants is so simple,
the seller may even offer these services on a per-user basis, such as where
the user requests
a particular configuration of container, and the seller merely assembles the
desired
configuration from selected components on-hand having the desired combination
of
features.
Method of ll~a~aufacturing
Refernng now to Fig. 7, an exemplary embodiment of the method of manufacturing
the container apparatus is disclosed. It will be appreciated that while the
following
embodiment is described in terms of the apparatus 300 of Fig. 3, the methods
may be
readily adapted to any of the variants or embodiments disclosed herein, such
adaptations
being readily implemented by those of ordinary skill.
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CA 02482286 2004-09-23
As shown in Fig. 7, the method 700 generally comprises forming the body 302 of
the container using a molding process (step 702). As previously described,
such molding
process may comprise injection, blow, or transfer molding, although blow,
molding is
selected in the illustrated embodiment based on, inter ~licz, its simplicity
and low per-unit
S cost. Texturing may also be applied during or after the molding process if
desired, as
previously described herein.
The molded body is then inspected and finished (including removing any molding
flash, and cutting off the blow dome at the end where the opening to the
container is
located) as necessary per step 704.
Next, the nylon glass-reinforced cap 304 is forrned by a molding process
(injection
molding) per step 506, and similar finishing to that of the body 302 performed
(step 708).
Lastly, the cap 304 is installed (threaded) onto the body 302 for final
assembly (step
710).
While seemingly simple, the foregoing method S00 underscores a salient
advantage
1 S of the present invention; i.e., its ultra-low cost to manufacture, owing
in large part to (i)
simplicity of design and (ii) selection of well understood and readily
available materials
and fabrication techniques. Use of more exotic composites and alloy components
(such as
in the prior art Bearilcade) and ABS sections which must be bonded together
(as in the
Model 812) invariably necessitate higher manufacturing costs, and hence higher
costs to the
end user. Similarly, the use of inserted fasteners (such as in the prior art
Bearikade and
Model 812) adds complexity and costs to the end user. Polycarbonate technology
is
ubiquitous, being used for example in larger volume commercial water bottles.
Design
features such as the aforementioned exclusion ridge 316 also obviate the need
for additional
components and mechanisms.
2S Hence, the carefully considered design of components and selection of
materials in
the present invention are inherently part of what is otherwise a comparatively
simple
manufacturing process 700. It is significant to note that this simplified
process would not be
possible under the prior art, however, since all prior ark designs necessitate
additional
manufacturing steps in relation to the process disclosed herein. Hence, the
exemplary
process 700 described above is just as significant for what is doss not
perform as vuhat it
does.
It can be appreciated that while certain aspects of the invention have been
described
in terms of a specific sequence of steps of a method, these descriptions are
only illustrative
of the broader methods of the invention, and may be modified as required by
the particular
-30-
CA 02482286 2004-09-23
application. Certain steps may be rendered unnecessary or optional under
certain
circumstances. Additionally, certain steps or functionality may be added to
the disclosed
embodiments, or the order of performance of two or more steps permuted. All
such
variations are considered to be encompassed within the invention disclosed and
claimed
herein.
While the above detailed description has show~.~a, described, and pointed out
novel
features of the invention as applied to various embodiments, it will be
understood that various
omissions, substitutions, and changes in the form and details of the device or
process
illustrated may be made by those skilled in the art without departing from the
invention. The
foregoing description is of the best mode presently contemplated of carrying
out the invention.
This description is in no way meant to be limiting, but rather should be taken
as illustrative of
the general principles of the invention. The scope of the invention should be
determined with
reference to the claims.
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